Container porvided with resealable cover adhered to the container by an adhesive

ABSTRACT

A resealable container comprising an at least semi rigid receptacle with an opening, a lip surrounding the opening, a closure for closing the opening, and an adhesive. The adhesive provides a releasable and resealable bond between the closure and the lip, substantially all of the adhesive remaining on one of the closure or the lip when the bond is released.

The invention relates to a container such as a resealable container for soft fruit or other items.

The area of soft fruit retailing has many difficulties and it would be beneficial to producer, supplier and consumer to have a container to store soft fruit between field and table which would allow the consumer easy access and where the life of the fruit would be extended for as long as possible. The present invention provides such a container.

DISCLOSURE OF INVENTION

The present invention provides according to a first aspect a resealable container comprising:

an at least semi rigid receptacle with an opening, and a lip surrounding its opening; a closure for closing the opening, and

an adhesive bonding the closure to the lip, the adhesive providing a releasable and resealable bond between the closure and the lip of the receptacle, whereby when the bond is released substantially all of the adhesive remains on only one of the closure or the lip.

An at least semi-rigid receptacle includes a rigid receptacle as well as a semi-rigid receptacle.

Preferably the adhesive is such that the bond can be broken and resealed several times.

Said adhesive preferentially attaches to either the lip or the closure.

Preferably the adhesive is applied using hot melt at, for example, 180° C.

Alternatively, the adhesive is applied as a cold liquid and allowed to dry.

Preferably, the lip includes a substantially flat portion.

The lip may be between 2 mm and 6 mm wide.

BRIEF DESCRIPTION OF DRAWINGS

A preferred embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which:

FIG. 1 is a perspective view, partly cut away, of a punnet forming part of a container,

FIG. 2 is a perspective view of a closure for closing the opening of the punnet of FIG. 1, the closure being shown upside down with respect to the orientation of the punnet of FIG. 1, and

FIGS. 3 to 5 are partial cross sections showing the engagement and disengagement of the closure with the punnet.

FIG. 6 shows the punnet with closure attached.

DISCLOSURE OF PREFERRED EMBODIMENT

FIGS. 1 to 6 show a resealable container for soft fruit or other items. The container comprises an open-topped, rigid or semi-rigid receptacle in the form, of a so-called punnet 1 and a closure 5 for closing the open top 2.

The punnet is provided with a lip 3 surrounding the open top 2, said lip being substantially flat or including a substantially flat portion, the flat portion having a minimum width of 2 mm. The punnet 1 is form- or blow-moulded from a flat sheet of standard, food grade polypropylene. This polypropylene may be biodegradable due to the incorporation of an additive. The dimensions of the punnet 1 will be determined by the contents of the container.

FIG. 2 shows a closure 5 for closing the open top 2 of the punnet 1, the closure being made from a flat sheet of oriented polypropylene, which can be either a single, or laminated, extrusion and which may be micro-, macro- or non-porous. The sheet material will shear but not stretch in a particular direction due to the nature of oriented polypropylene.

The closure 5 may be manufactured as one of a series of closures in a strip 7 which may then be wound onto a reel for ease of handling during manufacture. Adhesive 4 is applied to the closure 5 (usually whilst it is still in a strip with other closures before winding up in a reel).

The adhesive bonding and sealing the punnet 1 and the closure 5 together is of a type that provides a releasable and resealable bond thereby allowing the closure to be partially or completely removed from the punnet 1 and then resealed to it. This allows, for example, the removal of a single piece of fruit by the consumer and the resealing of the container to maintain the fruit left in the container in a fresh condition. It is further desired that the bond should be airtight and consequently that the adhesive should remain bonded with one of the surfaces (in this case, where the receptacle is a punnet for fruit, with the closure 5, but in other cases it may be with the lip of the receptacle), but releasable from the other surface. Any adhesive that does not remain bonded with the one surface after opening but remains bonded irregularly to both surfaces makes the formation of an airtight seal on resealing unlikely or impossible.

A preferred adhesive is a hot-melt adhesive, which is applied to the closure 5 at a high temperature (140-180° C., typically substantially 180° C.) so as to form a substantially permanent bond with the material of the closure 5. The adhesive is applied in a desired pattern, typically in the shape of a band 4 of overall shape and dimension matching the shape and dimension of the flat portion of the lip 3 of the punnet 1. The adhesive may be in the form of a continuous surface or may be broken up into a patch pattern.

Thus in the manufacture of the container, the moulded punnet 1 is filled with the desired fruit. The strip 7 comprising a plurality of closures 5 is aligned with the top of the punnet 1 with the side with the adhesive facing the lip and aligned therewith (see FIG. 3). The closure 5 is engaged with the lip of the punnet (see FIG. 4) and separated from the remainder of the strip 7.

The container may then be sold to a consumer.

In order to open the container, the closure 5 may be peeled back from the lip of the punnet (see FIG. 5 and 6). The adhesive 4 remains substantially permanently bonded to the closure 5 but releases from the lip of the punnet 1 without leaving traces of adhesive likely to prevent formation of an airtight seal. If the consumer wishes to keep some of the fruit in the punnet, the closure is then reengaged with the lip of the punnet and once again the adhesive forms an airtight bond and seal. The process may be repeated several times so long as the lip remains clean.

If the container is to be used for a ‘living’ product, such as soft fruit, the closure 5 will normally be porous, as this will allow an appropriate atmosphere to be maintained within the container, which can double the shelf life of the product. Also, when the consumer opens and reseals the container after purchase, the life of the product left in the container will be extended much further than if the container remained open because the proper atmosphere within the container will be re-established. In order to provide the desired porosity of the closure, the sheet material from which the closure is made includes perforations of a size, which may be, for micro-porous material, below 100 μm, for macro-porous material above 100 μm. In an example, one or two lines of 40-80 μm perforations may be created by an electrostatic or laser perforating machine along the length of the film material comprising the closure.

The closure may also carry printing (directly or on a separate carrier layer such as paper), which is used as a label detailing the contents of the container.

The closure may also incorporate a means by which the consumer can establish whether the contents satisfy their requirements as to freshness—i.e.; a ‘smell box’, for the detection of odour.

The closure is dimensioned so that it overhangs 6 the lip 3 of the punnet 1 by 3 mm, (either all round the punnet or just at one edge or in one comer as appropriate), this overhang forming a means for the consumer to grip the closure for peeling the closure off the lip as is shown in FIG. 5 to open the container and expose the contents.

The width selected for the lip 3 of the punnet 1 will be determined by the strength of the resealable attachment required between the punnet and the closure 5. A lip width of up to 6 mm may be used, a wider lip allowing a stronger resealable attachment between the punnet 1 and the closure 5 but requiring more force to open. Factors, other than attachment strength may determine the lip width in each application, such factors including whether provision should be made for the application of a clip-on lid to the receptacle should the closure become unavailable or fail.

An alternative means of attaching the closure to the punnet (without requiring expensive machinery to apply to the closure a predetermined pattern of adhesive matching the flat surface) would involve manufacturing the cover from two sheets of film attached across their width by the adhesive wherein the sheets can peel apart. The shape and dimensions of the lip of the punnet is then cut out from the bottom sheet and peeled away leaving the adhesive attached to the closure.

Where the punnet is for food use, the polypropylene used and the oriented polypropylene used for the closure, should meet the required specification.

The adhesive 4 is a food grade, commonly available, permanent adhesive meeting the requirements of FDA regulation CFR.21.175.105 ‘Adhesives’ allowing for indirect food use which, when applied to a polypropylene surface using hot melt at 180° C., becomes preferentially attached to that surface and will form a non-permanent seal between it and the surface of the lip of the punnet.

Alternatively, in place of the hot-melt adhesive, one may use an adhesive which is applied cold and allowed to dry on the surface to which preferential attachment is required (i.e. the surface of the closure film), the adhesive forming a permanent bond with that surface and a releasable bond with the surface of the flat lip of the punnet.

Thus, using the materials identified here, the punnet 1, closure 5 and adhesive 4 form a resealable container wherein the adhesive 4 attaches preferentially to the closure 5.

The invention is not limited to the above example. For, example, in some circumstances it may be preferred to have the adhesive form a permanent bond with the receptacle and a resealable bond with the closure, or have the adhesive applied to the receptacle.

For non-food use, the adhesive (4) can be of a non-food grade standard.

Also, where stretching of the closure as the closure is pulled off the punnet is not a problem, other cheaper closure materials manufactured by a casting process may be used, such as polyester, polyethylene or other materials.

In addition, the punnet may also be made of other materials to suit a particular application (or cost) requirement and these may be polyester, polyethylene, polystyrene or other materials. 

1. A resealable container comprising: an at least semi rigid receptacle with an opening, and a lip surrounding the opening; a closure for closing the opening, and an adhesive bonding the closure to the lip, the adhesive providing a releasable and resealable bond between the closure and the lip of the receptacle whereby, when the bond is released, substantially all of the adhesive remains on only one of the closure or the lip.
 2. A container according to claim 1, wherein said adhesive is such that the bond can be broken and resealed several times.
 3. A container according to claim 2, wherein said adhesive preferentially attaches to the receptacle.
 4. A container according to claim 2, wherein said adhesive preferentially attaches to the closure.
 5. A container according to claim 2, wherein the adhesive is applied to the closure.
 6. A container according to claim 2, wherein the adhesive is applied to the receptacle.
 7. A container according to claim 1, wherein the adhesive is a food grade, permanent adhesive meeting the requirements for indirect food use.
 8. A container according to claim 1, wherein the adhesive is applied using hot melt.
 9. A container according to claim 1, wherein the adhesive is applied as a cold liquid and allowed to dry.
 10. A container according to claim 1, wherein the lip includes a substantially flat portion.
 11. A container according to claim 10, wherein the flat portion of the lip is between 2 mm and 6 mm wide.
 12. A container according to claim 1, wherein the closure is made from a flat sheet of oriented polypropylene.
 13. A container according to claim 1, wherein the closure overhangs the lip by 3 mm.
 14. A container according to claim 1, wherein the closure is manufactured in a strip, then reeled up.
 15. A container according to claim 1, wherein the closure is partially covered by adhesive,
 16. A container according to claim 1, wherein the closure includes a label incorporating information as to the contents of the container.
 17. A container according to claim 1, wherein the closure incorporates a “smell box”.
 18. A container according to claim 1, wherein the closure is a single sheet.
 19. A container according to claim 1, wherein the closure is a laminated extrusion.
 20. A container according to claim 1, wherein the closure is micro-porous, and includes perforations less than 100 μm.
 21. A container according to claim 1, wherein the closure is macro-porous, and includes perforations greater than 100 μm.
 22. A container according to claim 1, wherein the closure is non-porous.
 23. A container according to claim 1, wherein the receptacle is form or blow moulded from a flat sheet of standard, food grade polypropylene.
 24. A container according to claim 23, wherein the polypropylene is biodegradable.
 25. A container according to claim 1, wherein the receptacle is form or blow moulded from a flat sheet of standard, food grade polyethylene, polyester or polystyrene. 